Many photovoltaic (PV) arrays are mounted on structures that require discrete attachment points. For example, tile and slate roofs and various types of ground mounted structures may include a support structure for a PV array that requires attachment of the PV array to the structure at discrete locations in one of or both the x and y axes of a PV array mounting plane. In the case of tile roofs, this may be due to the difficulty of installing an attachment device at anywhere other than a specific place relative to the tile. For example, some tile products may only allow an attachment device to be installed within a small range of the overall reveal (length showing) of the tile and the underlying roof may require attachment to the rafters, which typically runs on a discrete schedule. Thus, locations for mounting along the y-axis may be restricted as by the tile and locations for mounting along the x-axis may be restricted as by the locations of the rafters. Ground mount structures may also require discrete attachment points in the x and/or y axes as may be due to fixed locations of the structural members and/or the need to line up the structural members with specific locations on the PV module.
Some attempts have been made to address the need for discrete attachment point mounting systems. Most utilize long rails to span between discrete attachment points, thereby freeing up the x and/or y axes. The rails may be connected directly to the PV module frame as by a compression clamp. The rails may be connected to the support structure below as by means of an attachment device such as a tile hook, standoff, hanger bolt, false tile, or mounting foot.
Such conventional systems suffer from a number of drawbacks. The long rails utilized, which can be often 10-20 feet long, may be difficult to warehouse, ship, and move onto a roof, or other support surface. These rails may also limit mounting options on complicated roofs which may have numerous smaller roof surfaces and/or numerous obstructions (such as vent pipes, chimneys, and so on) since rails may need to be cut on site, potentially wasting time and materials. Since rafters typically run in the direction from ridge to gutter, conventional long rail systems may be less cost-effective if the PV modules are oriented in “landscape” as opposed to “portrait” manner, since rails parallel to the rafters may require more total rail length or be prohibited, as by the PV module manufacturer or local building codes.
The mounting technology used to connect PV modules to these described long rails may also be cumbersome and time-consuming due to large numbers of small parts, including fasteners. The attachment devices utilized may also be expensive and time-consuming to install. Such conventional systems may further suffer from a lack of adaptability to uneven roof surfaces as well as time-consuming and unreliable grounding hardware. There may also be very little integration with other required equipment in the overall PV system, such as electrical junction and combiner boxes, wire management devices, and other equipment.
Prior discrete attachment point systems and related photovoltaic arrays may frequently require more attachment devices and/or more material per device than needed for acceptable structural performance of the system. For example, typical tile roof mounting systems, which may not interconnect the rows, may require two rows of rails per row of PV modules, or may require rails that traverse the distance under an entire row or column of PV modules, or at least many modules in a row or column of PV modules. This constraint may limit the ability of a system designer to optimize the structural support system so that the level of support provided is substantially matched to the level of support required, based on various site conditions such as wind, snow, roof structure, and so on. Lack of structural optimization could waste a significant quantity of materials relative to a more optimized approach.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the figures.